Sectional dry-dock



Vbut not so in deep water, as it frequently UNITED STATES PATENT oEEIoE.

SAMUEL LOVEIJAND, OF ASTORIA, NEW hYORK.

SECTIONAL DRY-DOCK.

Specification of Letters Patent No. 10,600, dated March 7,1854; Anteda'ted September 7,V 1853.

To all whom Z5 may concern Y Be it known that I, SAMUEL LovELAND,

of Astoria, Long Island, and State of New York, have invented new and useful Improvements in Sectional Floating Dry- Docks, and that the following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, making a part of this specification.

This invention is an important improvement on my floating dry dock patented Feby. 5, 1847, by which I am enabled to overcome several ditliculties practically found to exist in the use of said dock, the first of which was that of depending on my airv chambers, placed above the hollow guards, in the gallows frame for steadying my dock, whereas the eHnect was, the canting of dock before the guards were raised suliciently above the surface or even reached it. This arose in part from the diliiculty of withdrawing the water equally in the two tanks or separate floats constituting a section of the float. As a leak would occur in one while t-he other remained tight j it was found impossible without eXtra care to withdraw equal quantities of water and admit equal quantities of air through the open pipes in the end tank, rising above the surface of the water. This canting of the dock rendered Vthe canting of the vessel thereon inevitable. not tobe dreaded, as the application of the pumps on the lower side remedied the evil,

has occurred that the dock itself has sunk.

Another diiculty existing was that of. throwing the whole weight of the vessely raised on the center of the cross timbers or cradle pieces (uniting the separate iloats,) by which they were frequently fractured, and in one instance the ventire floats rose from thiscause leaving the vessel between them. A further difficulty eXistingin all other docks was that of getting at the keel,

or center board trunk, when repairs were necessary, without involving the necessity of using high blocks or that of the workman lying on his back when making these repairs. Also that with the exception of the separate air tight chamber, which was liable to accident, there was no part of the float itself air tight or capable of contain- In shoal water this was ing air when subjected kto compression therem, as all other hollowy guard docks were open or unprovided with covers .capable of retaining compressed air.

Having thus setforth the practical' disadvant-ages found to existfin my first dock, as well as in others, I will now proceed to'set forth the advantages of my sectional dock on which this application is based. First, by constructing each section of the dock of a single float, and bythe mode of framing the principal timbers thereof,- connecting them with each other, and with the vmore greater strength in supporting the weight of the vessel, inasmuch as the incumbent weight instead of being thrown on the center of the cradle pieces is transferred tothe string pieces andfguards, by which all liability of depression ofthe dock and strainsol ing of the vessel is avoided. I also Construct it at less expense of labor and with more buoyant power, consequent upon the reduction of timber, giving the space it would occupy to the ocoupance of airv instead thereof., Secondly, by the introduction of two water tight bulk heads -one .on

each side of the center of the iloat,l I ani enabled to createa water ballast inl the ftank i thus formed, directly under-and' in the vertical line passing through the keel ofthe vessel when rising, which in conjunction with the air chambers controllable by'valves in ythe guards, I obviate allv difficulty inthe canting alluded to in speaking of my first dock; This water tank may bedischarged of its water into the body of the float by,

valvesV when the float is abovewatenwhen it is necessary to have access to theun'der side `of the keel or center board trunk, and as it usually is aboutfour feet wide, it affords free access in such repairs. It isl also of advantage in giving greater buoyancy to the dock when pumped out, when thev air chambers of theV guards are not suificient.4 Its chief use is that ofa ballast in the center of the dock, serving the purpose as much so as if it were pounds of iron instead of water. These bulk heads also serve the purpose of preventing water in either end of the float surging from end to end therein. This water ballast or tank in connection witlirthe air tight guards aords us the means of readily trimming the dock to a level and preserving its equilibrium. And by the inw troduction of the safety air tanks into the air tight guards, all danger of accidental sinking ofthe dock itself is avoided,` even should the guards themselves b e stove or prove leaky, while by the conjoined. useof the tank in the center of each sectron, viz., tha't of furnishing ballast, and at the same time admitting of ready access (by withdrawal of the water) to the keel of the incumbent vessel forrepair of the same.

To enable others skilled in the art to construct and use my invention, I will proceed to describe a single section Y of the dock, any number of which may be used, being connected together in the usual method.

25 Figure lis an isometrical view. Fig. 2, an elevation exhibiting the framing. Fig. 3, a plan showing the tank or vater ballast and the mode of planking the` bottom ofthe float exhibited at .K to the left of the figure.

The bottom of the section is a parallelograln about 80 feet long by 2O wide and instead 'of being divided as in my former dock I into two floats connected by the cradle pieces, it is a single one, the framing of which will be hereafter described.

A` A, represent wat-er tight chambers formed of the planked sides, ends of the float, bottom thereof and two bulk heads, extending: from side to side, placed equi- Ilb distant from thelcenter of the float so as to leave a space on the bottomV of about 4 Vfeet wide and the depth of the float, say 5 or 6 feet; The deck extends from the guards to therbulk heads, but does not cover the tank C; not but it may be covered over.

The frame of the dock is madeV of light timbeigbut so arranged as to produce the best possible effect, both with regard to strength and buoyancy.

5o a a represent braces united at the center of the dock and extending nearly to the ends of the string or base pieces Z). They are secured thereto by ancho-r bolts, pins, &c. This mode of framing is applied under eachcradle tim ber (see Fig. 2) of the dock. The principle of capacity of the arch to resist the incumbent weight when over the junction of a a, viz., at the center of the dock, willbe apparent, as well as capacity to overcome that ofdisplacement of the water causing resistance on the heels of the braces. This with the plan of planking the bottom of the float as seen at 7:, F ig. 3, transfers this resistance 55 from the heels of the braces to the center of the deck of the float, relieving the string piece or base b, as well as the` cradle timber all liability of fracture of the cradle pieces.

Iconnect these heels of the braces by stir-` rup bolts with cross timbers e e placed on the upper sides of the ends of the cradle pieces f f. These cross timbers are placed adjoining the hollow guards or more buoyant portions of the dock.

g, g', in Figs. v2 and 3, are cross sills secured on the under side of the string pieces and the planking K is spiked to them, extending from end to end of the dock forming a continuous bottom. The air chambers B B are raised on the ends of the floats and on the deck thereof and are made tight, they communicate with the buoyant chambers A vA. In the top of each chamber is a lvalve zl opening inwardly, `controlled by a thumb lscrew and rod 2'. passingv throughf a brdle on the chamber. Through the top of the chamber also passes (air tight) a set screw j, to arrest at any desired height the safety air tanks d, inside` of B B, when thev water in A A causes them to float.

. f, and with the view of equalizing or divid-` ing the strain on the float and to prevent D D are pumps entering the body of the y the vessel; then opentheair valves z, in the several guards B, also the inlet valves E, E, bylwhich the dock is sunk the desired depth. If it isvery buoyant eXtra ballast may be necessary. It is then floated under the vessel if in deep water, or the `vessel floated on the dock. The valves E E are then to be closed and the discharge pumps D D started, 4

which raising the several sections bring the keel blocks H, H, under the keel, when all the sections are thus brought to bear. The puppets or bilge blocks are adjusted to the sides of the vessel; then the pumps of all the sections are worked simultaneously andthe vessel is raised to a desired height, bringingrthe decks of the floats sufiiciently high above the water. The air valves z, are then to be closed and secured and the vessel is ready for repair.

It may be proper to advert to accidents occuring to other docks, such as those at New Orleans and atV St. Louis, in which they were sunk by leakage, occuring not from eX- traordinary accident, but arising from the mode of cross planking on the bottom `of each section (instead of lengthwise) which 1n the strain on the center caused these laterally placed seams to open and leak. In my plan of placing the planking K lengthwise on the bottom this was prevented and that additional strength was given the float as before described.

I am aware that a water ballasthas been used extending from stem to stern of a life boat, for the purpose of righting the same;

and am also aware that space between separate floats is not new. But y What I claim as my invention and desire to secure by Letters Patent isl. The transversely placed tank, trunk or water chamber C of each section of the dock forming not only a central water ballast in the float directly under the keel of the vessel to be raised, but when empty, a dry tank for the purpose of giving access to the keel in repairs@ 2. I also claim the tank, trunk or chamber C, in combination with the buoyant chambers or floats A, A, hollow guards or chambers B B, orfwhen combined with.

' SAMUEL LOVELAND.

Witnesses JOHN F. CLARK, SAML. GRUBB. 

